1. Field of the Invention
The present invention relates to an electronic equipment, and more particularly to an electronic equipment provided with two-dimensional (hereinafter, “2D”) and three-dimensional (hereinafter, “3D”) displaying functions.
2. Description of the Background Art
In recent years, advanced electronic equipment has been developed including portable equipment such as portable terminals, portable personal computers and mobile phones, information equipment such as desktop personal computers, and audio/video equipment.
For example, a mobile phone with a 3D display having a 3D displaying function and allowing switching between 2D/3D displays has been proposed. In this conventional mobile phone, to switch between the 2D/3D displays, a lenticule located above a liquid crystal display as a displaying body is made movable to allow a change of displaying regions of a 2D displaying portion and a 3D displaying portion (e.g., Japanese Patent Laying-Open No. 2001-251403, pages 1–12, and FIG. 9).
A configuration of a 3D display switchable with a 2D display is described with reference to FIGS. 9–14.
FIG. 9 shows a layout of pixels of a liquid crystal device (LCD) of a standard type. The LCD is used for a color display, and is formed of pixels of red (R), green (G) and blue (B). The pixels are arranged in columns Col0–Col5 where the red, green and blue pixels are arranged in a vertical direction. The leftmost column Col0 of the pixels corresponds to the leftmost strip of a displayed image, and the adjacent column Col1 to the right corresponds to the next strip of the image, and so on.
The display shown in FIG. 10 is used for a stereoscopic 3D display. The 3D display includes a liquid crystal display device (having a polarizing plate) 101 which serves as a spatial light modulator for adjusting light from a backlight 102 in accordance with the content of the image to be displayed. A parallax optic cooperates with liquid crystal display device 101 to form a viewing window. Hereinafter, the optical configuration of the display device in a state causing parallax is called the “parallax optic”. FIG. 10 shows an automatic stereoscopic 3D display of a front parallax barrier type which includes a parallax barrier 103 as the parallax optic. Parallax barrier 103 includes a plurality of slits 104 which extend in a vertical direction and are arranged at regular intervals in a lateral direction in parallel with each other. Each slit 104 is positioned at a center of a pair of pixel columns of different colors. For example, slit 104 in FIG. 10 is aligned with the column 105 of blue pixels and the column 106 of green pixels.
Left and right image data are provided to liquid crystal display device 101 of a type shown in FIG. 10 in a manner shown in FIG. 11, to ensure proper arrangement of left and right viewing windows. In FIG. 11, color image data of the leftmost strip of the left image is displayed by the red, green and blue pixel columns denoted by “Col0 left”. Similarly, color data of the leftmost strip of the right eye view is displayed by the pixel columns denoted by “Col0 right”. With this arrangement, the image data of the left and right views are reliably transmitted to appropriate left and right viewing windows. This arrangement also ensures that all the three pixel colors R, G and B are used to display each view strip.
In the layout shown in FIG. 11, different from the layout shown in FIG. 9, the red and blue pixels in the leftmost column display image data of the left view, while the green pixels in the leftmost column display image data of the right view.
In the next column, the red and blue pixels display image data of the right view, whereas the green pixels display image data of the left view. As such, in the case where a standard liquid crystal display device of a type shown in FIGS. 9–11 is employed, it is necessary to interlace image data of the left and right views by “replacing” the green components with each other between the RGB pixel columns. It is of course possible to replace red or blue components, instead of the green components, depending on setting of a display.
FIG. 12 shows a portion of a display controller. Data to be displayed are provided in series on a data bus 120. Addresses defining positions of the pixels on a screen are supplied on an address bus 121. Data bus 120 is connected to inputs of a number of banks of random access memories such as memories (video random access memories, VRAM) 122 and 123 (two memories are shown in the drawing). Address bus 121 is connected to a memory management system 124. Memory management system 124 converts a screen address to a memory address to be supplied to address inputs of memories 122 and 123.
Output ports of memories 122 and 123 are connected via a latch circuit 130 to a fast in fast out (FIFO) register 125 of a video controller 126. Memories 122 and 123 and register 125 are controlled such that respective pixel data are read out of memories 122 and 123 alternately and supplied to a displaying memory (VRAM) 127 in a correct order. Displaying memory 127 is provided between FIFO register 125 and a driver circuit of liquid crystal display device 101, and temporarily stores the arranged display data.
FIG. 13 shows latch circuit 130 in more detail. Latch circuit 130 includes latches 140 and 141 connected to output ports of memories 122 and 123, respectively. Each of latches 140 and 141 includes 24 one-bit latches which are arranged in groups of 8 latches latching R, G and B data from the corresponding memory. Latches 140 and 141 have latch enable inputs collectively connected to an output of a timing generator 128 supplying a latch enable signal L.
Latch circuit 130 further includes three switching circuits 142, 143 and 144. Each switching circuit includes eight switching elements having control inputs collectively connected to an output of timing generator 128 supplying a switching signal SW. Timing generator 128 further has an output for supplying a write enable signal F to register 125.
It is noted that switching circuit 143 corresponding to G data is switched to latch circuit 140, 141 different from that to which other switching circuits 142 and 144 are switched.
Latch enable signal L attains a “high” level when display data are available at the output ports of memories 122 and 123. Thus, latches 140 and 141 latch the display data. Immediately after latch enable signal L returns to a “low” level, switching signal SW rises to a “high” level. Next, switching circuits 142, 143 and 144 are switched to the states shown in FIG. 13, and the R, G and B outputs of latch 140 are connected to register 125. Thereafter, write enable signal F is supplied to register 125, and the RGB data from latch 140 are written into register 125. Write enable signal F is then disabled to prevent additional writing of data to register 125 until application of a next write enable signal.
Thereafter, switching signal SW attains a “low” level, and switching circuits 142, 143 and 144 connect the output of latch 141 to register 125. Write enable signal F is then generated, and data from latch 141 is written into register 125. At the same time, the data having been written into register 125 are written into displaying memory 127. Next, latch enable signal L rises to a “high” level, and the same processing is repeated. As such, the data are written from memories 122 and 123 alternately to register 125. Correspondingly, the data having been written into register 125 are sequentially written into displaying memory 127. The processing is repeated until data necessary for display of one image screen is written into displaying memory 127.
Processing in the case of writing 2D or monoscope data which should be displayed for both eyes of an observer is as follows. The parallax optic by parallax barrier 103 is removed from the light path of liquid crystal display device 101. The monoscope pixel data are directly input and stored in displaying memory 127 of FIG. 12 for execution. In the 3D display mode, the left eye image and the right eye image each have a resolution half the horizontal spatial resolution of liquid crystal display device 101. When the display operates in the 2D or monoscope mode, the left and right eye images each have a resolution twice the resolution in a lateral direction of liquid crystal display device 101 when it operates in the 3D display mode.
FIG. 14 shows by way of example a display device configured to switch and display the 2D and 3D images by selectively forming a parallax optic. In this display device, whether to cause parallax between the two eyes of the observer may be made selectable in an electrical manner. Here, as the parallax optic, the liquid crystal device as described above, i.e., 2D/3D switching liquid crystal device (LCD) 150, and a patterning phase contrast plate 151 are used. Switching liquid crystal device 150 has a mat electrode for switching the entire surface between 3D and 2D images. Patterning phase contrast plate 151 replaces one of the two polarizing plates of the liquid crystal device. The portions in FIG. 14 having substantially the same functions as those in FIG. 10 are denoted by the same reference characters. In the example shown in FIG. 14, a parallax barrier 103′ is placed on the back surface of liquid crystal display device 101 or on the backlight 102 side. Alternatively, it may be placed on the front side of liquid crystal display device 101, as shown in FIG. 10.
In the arrangement shown in FIG. 14, a voltage is not applied to switching liquid crystal device 150 when a 3D image is displayed. Thus, the internal liquid crystal molecule maintains the rotated state. Slits, substantially the same as slits 104 of parallax barrier 103 in FIG. 10, are formed according to a pattern of patterning phase contrast plate 151, by virtue of the polarizing characteristic of the light with respect to patterning phase contrast plate 151. When a 2D image is displayed, a voltage is applied to switching liquid crystal device 150, and rotation of the liquid crystal molecule is cancelled. Thus, patterning phase contrast plate 151 is no longer affected by the incident light, irrelevant to presence or absence of a pattern, so that formation of slits is cancelled.
Alternatively, a liquid crystal display device including a pair of polarizing plates for switching between 2D and 3D displays may be employed to selectively display a display pattern of the display device similar to the pattern of parallax barrier 103, as described in Japanese Patent Laying-Open No. 5-122733 or No. 7-236174.
A 2D image can be displayed on the automatic stereoscopic 3D display as shown in FIG. 10 provided with a mechanical parallax optic, by making left and right displayed screen images same with each other, with parallax barrier 103 being attached. In this case, however, the display itself has the parallax optic formed. Thus, even when a 2D image is displayed, a user will be affected by the parallax optic when seeing the display.
On the other hand, selectively forming the parallax optic as shown in FIG. 14 is advantageous in that display of the 2D image is unaffected by the parallax. That is, in the case of arrangement of FIG. 14, when the 2D-image display is selected, the parallax optic is not formed or otherwise formed only in a portion of the displayed region. At this time, the display has a device structure substantially the same as in a normally used liquid crystal display device. Thus, the user can easily recognize the image from any position, unaffected by the parallax of the left and right eyes.
It is tiresome to see a stereoscopic 3D display in a moving vehicle or continuously for a long time. Further, there are some who cannot make the 3D image in their heads by nature. In such cases, it is desirable to switch the 3D image display to the 2D image display. In addition, if the 2D-image display can be switched to a stereoscopic or 3D-image display, an interesting display having an impact on the user will be provided.